In a support structure for attaching an elongated component such as a fuel pipe, brake pipe or wire harness of an automobile, it is desired to have vibration absorbability for preventing vibration of an automobile body from transmitting to the above pipe or the like. Heretofore, for the purpose of such vibration insulation, a technique of attaching the pipe or the like to a fastener with winding a rubber vibration insulator around the pipe or the like has been typically employed. In view of a poor workability of this technique, it is desired to provide a vibration insulation function to the fastener itself. From this point of view, Japanese Patent Laid-Open No. 07-310866 discloses a clip fastener suitable for holding a fuel pipe, in which a pipe holder portion is connected to a support through a hollow portion. This clip is intended for supporting an elongated component such as a pipe, and designed to prevent vibration transmission from the pipe or the like to an automobile body or the like (or vibration transmission from the automobile body to the pipe or the like) as much as possible. In the disclosed clip fastener for a pipe or the like, a structure having four pipe holder portions arranged in line is disclosed as an embodiment. However, a significant difference in vibration insulation characteristics can be caused between the line center and the line ends of the pipe holder portion.
Japanese Patent Laid-Open No. 2000-18433 discloses a fastener for a pipe or the like, which has an improvement in the above point. FIGS. 1 and 2 show this fastener. In FIG. 1, the fastener 1 comprising a base 2 and a pipe holder portion 3 supported by the base 2. The pipe holder portion 3 includes a curved wall 6 defining a recess 5 for receiving an elongated component such as a pipe therein, and a resilient holding finger 7 extending obliquely from the end of the curved wall 6 into the recess. The pipe holder portion 3 is supportedly connected to the base 2 through a hollow tubular cushion portion 9. The fastener 1 provides excellent vibration insulation characteristics between the base 2 and the pipe holder portion 3. Further, even if a plurality of retaining portions 3 are arranged in line, the fastener 1 desirably provides unnoticeably suppressed difference in vibration insulation characteristics between the respective retaining portions 3.
As shown in FIGS. 1 and 2, in the fastener disclosed in the aforementioned Japanese Patent Laid-Open Publication No. 2000-18433, the end of the curved wall 6 of the pipe holder portion 3 is connected to the end of the adjacent curved wall 6 of another pipe holder portion 3 through a flexible V-shaped thin connecting piece 10. The end of the curved wall 6 of the pipe holder portion 3 is also connected to the end of the adjacent wall 13 of the base through a flexible thin connecting piece 11 arranged obliquely. While these flexible thin connecting pieces 10 and 11 were desirable in terms of vibration insulation, it was found that there was the need to be improved in a fastening force of the pipe holder portion 3. This will be explained with reference to FIG. 2 showing the portion designated by the circle 14 in FIG. 1. In FIG. 2, when a force of pushing out a pipe in the direction of the arrow 17 is applied to a pipe 15 held by the pipe holder portion 3, the thin connecting piece 10 is, for example, deformed from the angle “a” to the angle “b” in FIG. 2 because the thin connecting pieces 10 and 11 are flexible. Then, the curved wall 6 at the right side of FIG. 2 is deformed rightward. Simultaneously, the thin connecting piece 11 is also deformed slightly, and thereby the curved wall 6 adjacent to the wall 13 is deformed leftward. As a result, the inlet of the curved wall 6 is widely opened, and the resilient holding finger 7 is displaced rightward with respect to the pipe 15. Thus, it was found that the pipe 15 could be pulled out of the pipe holder portion 3 due to insufficiently degraded engagement force of the pipe 15.
It is therefore an object of the present invention to provide a fastener for holding an elongated component such as a pipe to an attachment member such as an automobile body, capable of maintaining a fastening force of the elongated component such as a pipe at high levels while maintaining insulating characteristics against vibration transmitted from the pipe or the like to an automobile body or vice versa at high levels.